diff --git a/js/src/ion/MCallOptimize.cpp b/js/src/ion/MCallOptimize.cpp
index 581603541d1..8f2e33843c5 100644
--- a/js/src/ion/MCallOptimize.cpp
+++ b/js/src/ion/MCallOptimize.cpp
@@ -880,15 +880,15 @@ IonBuilder::inlineUnsafeSetElement(CallInfo &callInfo)
      */
 
     for (uint32_t base = 0; base < argc; base += 3) {
-        uint32_t arri = base + 1;
-        uint32_t idxi = base + 2;
+        uint32_t arri = base + 0;
+        uint32_t idxi = base + 1;
 
         types::StackTypeSet *obj = getInlineArgTypeSet(callInfo, arri);
         types::StackTypeSet *id = getInlineArgTypeSet(callInfo, idxi);
 
         int arrayType;
-        if (!oracle->elementAccessIsDenseNative(obj, id) &&
-            !oracle->elementAccessIsTypedArray(obj, id, &arrayType))
+        if (!oracle->elementWriteIsDenseNative(obj, id) &&
+            !oracle->elementWriteIsTypedArray(obj, id, &arrayType))
         {
             return InliningStatus_NotInlined;
         }
@@ -903,20 +903,20 @@ IonBuilder::inlineUnsafeSetElement(CallInfo &callInfo)
     current->push(udef);
 
     for (uint32_t base = 0; base < argc; base += 3) {
-        uint32_t arri = base + 1;
-        uint32_t idxi = base + 2;
+        uint32_t arri = base + 0;
+        uint32_t idxi = base + 1;
 
         types::StackTypeSet *obj = getInlineArgTypeSet(callInfo, arri);
         types::StackTypeSet *id = getInlineArgTypeSet(callInfo, idxi);
 
-        if (oracle->elementAccessIsDenseNative(obj, id)) {
+        if (oracle->elementWriteIsDenseNative(obj, id)) {
             if (!inlineUnsafeSetDenseArrayElement(callInfo, base))
                 return InliningStatus_Error;
             continue;
         }
 
         int arrayType;
-        if (oracle->elementAccessIsTypedArray(obj, id, &arrayType)) {
+        if (oracle->elementWriteIsTypedArray(obj, id, &arrayType)) {
             if (!inlineUnsafeSetTypedArrayElement(callInfo, base, arrayType))
                 return InliningStatus_Error;
             continue;
@@ -938,9 +938,9 @@ IonBuilder::inlineUnsafeSetDenseArrayElement(CallInfo &callInfo, uint32_t base)
     // Furthermore, note that inference should be propagating
     // the type of the value to the JSID_VOID property of the array.
 
-    uint32_t arri = base + 1;
-    uint32_t idxi = base + 2;
-    uint32_t elemi = base + 3;
+    uint32_t arri = base + 0;
+    uint32_t idxi = base + 1;
+    uint32_t elemi = base + 2;
 
     MElements *elements = MElements::New(callInfo.getArg(arri));
     current->add(elements);
@@ -1073,8 +1073,10 @@ IonBuilder::inlineNewDenseArrayForParallelExecution(CallInfo &callInfo)
         return InliningStatus_Error;
     templateObject->setType(typeObject);
 
+    callInfo.unwrapArgs();
+
     MParNewDenseArray *newObject = new MParNewDenseArray(graph().parSlice(),
-                                                         callInfo.getArg(1),
+                                                         callInfo.getArg(0),
                                                          templateObject);
     current->add(newObject);
     current->push(newObject);
diff --git a/js/src/ion/TypeOracle.cpp b/js/src/ion/TypeOracle.cpp
index 82671c55852..aaa2ad3cb19 100644
--- a/js/src/ion/TypeOracle.cpp
+++ b/js/src/ion/TypeOracle.cpp
@@ -290,19 +290,32 @@ TypeInferenceOracle::inArrayIsPacked(UnrootedScript script, jsbytecode *pc)
 bool
 TypeInferenceOracle::elementReadIsDenseNative(RawScript script, jsbytecode *pc)
 {
-    return elementAccessIsDenseNative(script->analysis()->poppedTypes(pc, 1),
-                                     script->analysis()->poppedTypes(pc, 0));
+    // Check whether the object is a dense array and index is int32 or double.
+    StackTypeSet *obj = script->analysis()->poppedTypes(pc, 1);
+    StackTypeSet *id = script->analysis()->poppedTypes(pc, 0);
+
+    JSValueType idType = id->getKnownTypeTag();
+    if (idType != JSVAL_TYPE_INT32 && idType != JSVAL_TYPE_DOUBLE)
+        return false;
+
+    Class *clasp = obj->getKnownClass();
+    return clasp && clasp->isNative();
 }
 
 bool
 TypeInferenceOracle::elementReadIsTypedArray(RawScript script, jsbytecode *pc, int *arrayType)
 {
-    if (!elementAccessIsTypedArray(script->analysis()->poppedTypes(pc, 1),
-                                   script->analysis()->poppedTypes(pc, 0),
-                                   arrayType))
-    {
+    // Check whether the object is a typed array and index is int32 or double.
+    StackTypeSet *obj = script->analysis()->poppedTypes(pc, 1);
+    StackTypeSet *id = DropUnrooted(script)->analysis()->poppedTypes(pc, 0);
+
+    JSValueType idType = id->getKnownTypeTag();
+    if (idType != JSVAL_TYPE_INT32 && idType != JSVAL_TYPE_DOUBLE)
+        return false;
+
+    *arrayType = obj->getTypedArrayType();
+    if (*arrayType == TypedArray::TYPE_MAX)
         return false;
-    }
 
     JS_ASSERT(*arrayType >= 0 && *arrayType < TypedArray::TYPE_MAX);
 
@@ -393,13 +406,14 @@ TypeInferenceOracle::elementReadGeneric(UnrootedScript script, jsbytecode *pc, b
 bool
 TypeInferenceOracle::elementWriteIsDenseNative(HandleScript script, jsbytecode *pc)
 {
-    return elementAccessIsDenseNative(script->analysis()->poppedTypes(pc, 2),
+    return elementWriteIsDenseNative(script->analysis()->poppedTypes(pc, 2),
                                      script->analysis()->poppedTypes(pc, 1));
 }
 
 bool
-TypeInferenceOracle::elementAccessIsDenseNative(StackTypeSet *obj, StackTypeSet *id)
+TypeInferenceOracle::elementWriteIsDenseNative(StackTypeSet *obj, StackTypeSet *id)
 {
+    // Check whether the object is a dense array and index is int32 or double.
     JSValueType idType = id->getKnownTypeTag();
     if (idType != JSVAL_TYPE_INT32 && idType != JSVAL_TYPE_DOUBLE)
         return false;
@@ -414,16 +428,15 @@ TypeInferenceOracle::elementAccessIsDenseNative(StackTypeSet *obj, StackTypeSet
 bool
 TypeInferenceOracle::elementWriteIsTypedArray(RawScript script, jsbytecode *pc, int *arrayType)
 {
-    return elementAccessIsTypedArray(script->analysis()->poppedTypes(pc, 2),
-                                     script->analysis()->poppedTypes(pc, 1),
-                                     arrayType);
+    return elementWriteIsTypedArray(script->analysis()->poppedTypes(pc, 2),
+                                    script->analysis()->poppedTypes(pc, 1),
+                                    arrayType);
 }
 
 bool
-TypeInferenceOracle::elementAccessIsTypedArray(StackTypeSet *obj, StackTypeSet *id, int *arrayType)
+TypeInferenceOracle::elementWriteIsTypedArray(StackTypeSet *obj, StackTypeSet *id, int *arrayType)
 {
     // Check whether the object is a typed array and index is int32 or double.
-
     JSValueType idType = id->getKnownTypeTag();
     if (idType != JSVAL_TYPE_INT32 && idType != JSVAL_TYPE_DOUBLE)
         return false;
diff --git a/js/src/ion/TypeOracle.h b/js/src/ion/TypeOracle.h
index 7a57b33cc01..380b2ce9525 100644
--- a/js/src/ion/TypeOracle.h
+++ b/js/src/ion/TypeOracle.h
@@ -111,9 +111,15 @@ class TypeOracle
     virtual bool elementWriteIsDenseNative(HandleScript script, jsbytecode *pc) {
         return false;
     }
+    virtual bool elementWriteIsDenseNative(types::StackTypeSet *obj, types::StackTypeSet *id) {
+        return false;
+    }
     virtual bool elementWriteIsTypedArray(RawScript script, jsbytecode *pc, int *arrayType) {
         return false;
     }
+    virtual bool elementWriteIsTypedArray(types::StackTypeSet *obj, types::StackTypeSet *id, int *arrayType) {
+        return false;
+    }
     virtual bool elementWriteNeedsDoubleConversion(UnrootedScript script, jsbytecode *pc) {
         return false;
     }
@@ -123,12 +129,6 @@ class TypeOracle
     virtual bool elementWriteIsPacked(RawScript script, jsbytecode *pc) {
         return false;
     }
-    virtual bool elementAccessIsDenseNative(types::StackTypeSet *obj, types::StackTypeSet *id) {
-        return false;
-    }
-    virtual bool elementAccessIsTypedArray(types::StackTypeSet *obj, types::StackTypeSet *id, int *arrayType) {
-        return false;
-    }
     virtual bool arrayResultShouldHaveDoubleConversion(UnrootedScript script, jsbytecode *pc) {
         return false;
     }
@@ -259,9 +259,9 @@ class TypeInferenceOracle : public TypeOracle
     bool elementReadIsPacked(UnrootedScript script, jsbytecode *pc);
     void elementReadGeneric(UnrootedScript script, jsbytecode *pc, bool *cacheable, bool *monitorResult, bool *intIndex);
     bool elementWriteIsDenseNative(HandleScript script, jsbytecode *pc);
-    bool elementAccessIsDenseNative(types::StackTypeSet *obj, types::StackTypeSet *id);
+    bool elementWriteIsDenseNative(types::StackTypeSet *obj, types::StackTypeSet *id);
     bool elementWriteIsTypedArray(RawScript script, jsbytecode *pc, int *arrayType);
-    bool elementAccessIsTypedArray(types::StackTypeSet *obj, types::StackTypeSet *id, int *arrayType);
+    bool elementWriteIsTypedArray(types::StackTypeSet *obj, types::StackTypeSet *id, int *arrayType);
     bool elementWriteNeedsDoubleConversion(UnrootedScript script, jsbytecode *pc);
     bool elementWriteHasExtraIndexedProperty(RawScript script, jsbytecode *pc);
     bool elementWriteIsPacked(RawScript script, jsbytecode *pc);